Description from Flora of China
Avena clarkei J. D. Hooker, Fl. Brit. India 7: 278. 1896 ["1897"].
Perennial, loosely tufted. Culms erect from ascending base, (30–)50–70 cm tall, 0.5–1 mm in diam., pubescent especially below panicle, 1–3-noded. Leaf sheaths pubescent; leaf blades flat, 5–20 cm, 1.5–2(–4) mm wide, pubescent or scaberulous; ligule 1–2 mm. Panicle contracted, linear to lanceolate in outline, usually slightly loose, at least lower branches obvious, 5–18 cm, brown, green, or yellowish green; branches slender, erect or slightly spreading, pubescent. Spikelets 4–8.5 mm, florets 2 or 3; rachilla hairs ca. 1.5 mm; glumes unequal, narrowly lanceolate, lower glume 4–6 mm, upper glume 5–7.5 mm, apex sharply acute; lemmas narrowly lanceolate, 3.5–7 mm, scabrid, awned from near upper 1/3, apex usually 2-denticulate, teeth mucronate, occasionally subentire; awn strongly recurved at base, 4–8 mm, fine, not twisted; palea keels scabrid. Anthers 1.3–1.6 mm. Fl. Jul–Sep.
The boundary between Trisetum spicatum and T. clarkei is obscured by intermediates, which are probably the result of introgression between the two species. Trisetum clarkei tends to be a taller, more slender grass, with a slightly looser panicle of narrower spikelets with well-exserted awns.
Montane forests, among bushes, moist grassy mountainsides; 1900–4300 m. Gansu, Hubei, Qinghai, Shaanxi, Sichuan, Xinjiang, Xizang, Yunnan [E Afghanistan, NW India, Kashmir, Pakistan].